Kitabı oku: «Science and Medieval Thought»

PREFACE

IN the Middle Ages the old world had passed, and the vision of a new world came near to the eager and passionate hearts of many peoples. Lincoln and Wells, Amiens and Chartres, Florence and Assisi tell us of the glory of that vision; and bear witness of its flight: for with Gilbert, Galileo, Harvey and Newton the Middle Ages themselves became a phantom, and again the spirit of a new world appeared. Thus in the phases of time the world dies and is born again; fulfilling greater destinies. But the new are born in the cold bed of the elder worlds, and the young life is chilled, or a lustier offspring turns unnaturally to curse the dead; so in their decrepitude lay the Middle Ages upon modern life; and the Middle Ages were accursed, until certain pious men sought to reanimate their vestments and their formulas, and to set the hands back on the dial of the centuries; as manyminded man seeks wistfully to reanimate the simple wonders and beliefs of his childhood. Their ministry was no more than pious; the method of modern history wins the fruits of the past while casting away the shadow of its withered branches. This comparative method, first applied to the art and romance of the Middle Ages, so that every dilettante may now discourse to us of their evolution, has been applied also to the thought of the period; but its results, laid up in the closets of a few scholars, are as yet unfamiliar. It may then become one, who in no sense a scholar has strayed into these secret places, to try to distribute some lessons of the medieval thought which, to many of us, seems as sere and outworn as did the relics of Gothic shrines to our great-grandfathers. For, as in those medieval generations which lay nearest us the furnace had cooled, impatiently we had thrown metal and dross aside, and let our contempt for the dryness and pedantry of its latter days prevent our vision of the earlier time when the passion for knowledge bore up the world, and sought even to contain it. That dogma is not eternal is manifest to every wanderer in the streets of Toledo, yet the historian may well recall us to the study of a time when, by mystical or intellectual inspirations, men strove eagerly to know the meaning of life, its origins, and its issues; and may lead us to the discovery of the seeds and wells of its fertility. The Greeks prophesied that before man can determine his place and service in this world he must form some theory of the world as a whole; the ages of faith prophesied that great deeds must be born of great faith and of great conceptions.

To those who live only in the past, or only in the present, there seems in the discriminations of the comparative historian to be a certain cold-bloodedness. Are not the ears of this critic, so aloof from the murmuring of creed and controversy, are they not deaf to the voices of the spirit which he would interpret to us? A distinguished bishop who was among my hearers, with the fervour and gentle humour so well known in him, rallied me not for celebrating science but for putting religion to rout. Yet in our own day surely the argument is changed, not in form only but in very nature; so changed by the conceptions of evolution, which have entered the mind of churchman and layman alike, that not a few speculative beliefs are changing sides without the knowledge of the disputants; and he who thinks himself a defender of the faith may have joined the revolt. But if we no longer carry the colours of the troops of the past we shall collect our lessons from its strategies; and for one of these lessons a prelate of the King will give thanks with me, that his supremacy has palsied the arm of the inquisitor to strengthen that of the apostle.

An unsystematic reader of a subject finds it out of his power to make due acknowledgment of the help and advantage derived from expert authors. Much of the matter had seeded itself insensibly in his brain in the course of general reading and conversation; much of it again had been obtained more carefully from sources now forgotten. To the following authors I know I am profoundly indebted, as I am to many others to whose names and works I can now give no reference:

Hauréau, La Philosophie Scolastique, Ed. 1872;

Jowett, Dialogues of Plato (vol. III. p. 523);

Jourdain (Amable), Recherches critiques, Paris 1848;

Jourdain (Charles), Excursions historiques, Paris 1888 (and the Philosophie de St Thomas of the same author);

Ampère, Histoire litt. de la France avant le XIIme siècle;

Brucker’s Historia Critica Philosophiæ (English Ed., 1791);

Renan, Averroès, Paris 1866; the Philosophie périp. apud Syros; and the Peuples Sémitiques dans l’histoire de la civilisation, of the same author;

Roger Bacon, Westminster Review, 1864, two Articles (by Thomas Marshall, M.A. Oxon.);

Schmidt, Essai sur les Mystiques du XIVme siècle;

Benn, A. W., The Greek Philosophers, London 1882 (and many helpful essays in periodical literature);

Zeller, Die Philosophie der Griechen, 1881;

Krische, A. B., Theologische Lehre d. Griechischen Denker, Göttingen 1840;

Ueberweg, Grundriss d. Gesch. d. Phil. des Alterthums, Berlin 1867;

Gerlach und Traumüller, Gesch. d. physik. Experimentierkunst, Leipzig 1899;

Rashdall’s History of Universities; Haeser, Geschichte der Medicin, Jena 1875-82;

Baas, J. H., Gesch. d. Medicin, Stuttgart 1876;

Idem, Die geschichtliche Entwicklung des ärztlichen Standes, Berlin 1896;

Charles Daremberg (all his works);

Rousselot, Études sur la philosophie dans le Moyen Age, 1840;

Pattison, Casaubon, 1875;

Meunier, Francis, Essai sur la vie et les ouvrages de Nicole Oresme, Paris 1857.

Descartes, Epist. Cartes. 4to. Amst., 1668;

Plumpius, Fundamenta Med. Fol. Lovan., 1652;

Sylvii Op. Omn., 1679, p. 875;

Haller, Elem. Physiol., 1757, I. 3;

Tiedemann, Physiologie de l’homme, Paris 1831, I. 41;

Delle Chiaja, Instituzione di Anatom. e Fis. Comp., 1832, I. 13.

(The six last works are cited as being especially useful, among many others, to show the extent to which modern physiology, from Harvey onwards, is based upon vivisection; and that it could not have arisen or thriven otherwise. It was by the test of many vivisections that Plumpius was led to the honourable withdrawal of his opposition to Harvey.)

INTRODUCTION ¹

IN the many Harveian Orations which have been delivered since the death of the founder of modern physiology the direct aspects of his honour and of his work have been exhausted; of late years the orators have concerned themselves with indirect aspects. Some of my friends have said to me that they lack a perspective view of Harvey and his work; that even highly educated men have little sense of his relation to medieval thought, or of the evolution of medieval into modern thought. Of the several stars of the constellation – of Copernicus, Gilbert, Galileo, Harvey – they had some knowledge; but how came Harvey to be at Padua? how did science spring up in North Italy? did science arise out of the womb of medicine, or contrariwise? why did natural science not flourish in the thirteenth century, and was it not a great misfortune for Europe that it did not then flourish? what were the systems of thought which in the Middle Ages preceded, encouraged or thwarted the travail of the human mind, and what of good or ill do we owe to them? These and such questions it seemed not unfitting that a Harveian Orator of this latter day should consider. Now on the philosophy of the Middle Ages, and on its relation to the era of positive science of which Harvey was perhaps the chief pioneer, there lay in a drawer in my cabinet the confused and occasional notes of many years. An interest in this thorny subject, sown in my mind at first by accident, and reawakened by these enquiring friends, had for me the charms of an old fancy, and I trust some brief essay thereon may have a temporary service; if, that is, I can touch the imagination of my hearers, and after some broken fashion bring before them a vision of the nations swayed hither and thither upon the face of Europe by a thirst for knowledge of a kind different, both in its methods and in its aims, from our own.

This oration cannot have the merit of an original study. Had I the equipment I have not the leisure to carry my investigations to the sources. Yet I may have attained to some maturity of judgment herein by long occupation of my mind since, in 1863, my old friend Mr Thomas Marshall of Leeds, sometime of St John’s College, Oxford, interested me in the life and work of Roger Bacon, the only eminent forerunner of the great naturalists of the seventeenth century.

The art of the Middle Ages and the social and political history of the time have fascinated modern Europe; for medieval thought, though its phrases survive in their mouths, few persons have shown any care: yet to these conflicts we owe what we are. No great battles of mankind have been fought in vain; none of its great captains has deserved oblivion. Yet we shrug our shoulders at their uncouth or outlandish names; we assume that from their chairs there issued naught but rhetoric, casuistries and fallacies, and that their multitudinous disciples were silly moths.

Each period of human achievement has its phases of spring, culmination, and decline; and it is in its decline that the leafless tree comes to judgment. In the unloveliness of decay the Middle Ages are as other ages have been, as our own will be: but in those ages there was more than one outburst of life; more than once the enthusiasm of the youth of the West went out to explore the ways of the realm of ideas; and, if we believe ourselves at last to have found the only thoroughfare, we owe this knowledge to those who before us travelled the uncharted seas. If we have inherited a great commerce and dominion of science it is because their argosies had been on the ocean, and their camels on the desert. “Discipulus est prioris posterior dies”; man cannot know all at once; knowledge must be built up by laborious generations. In all times, as in our own, the advance of knowledge is very largely by elimination and negation; we ascertain what is not true, and we weed it out. To perceive and to respect the limits of the knowable we must have sought to transgress them. We can build our bridge over the chasm of ignorance with stored material in which the thirteenth century was poor indeed, we can fix our bearings where then was no foundation; yet man may be well engaged when he knows not the ends of his work; and the schoolmen in digging for treasure cultivated the field of knowledge, even for Galileo and Harvey, for Newton and Darwin. Their many errors came not of indolence, for they were passionate; not of hatred of light, for they were eager for the light; not of fickleness, for they wrought with unparalleled devotion; nor indeed of ignorance of particular things, for they knew many things: they erred because they did not know, and they could not know, the conditions of the problems which, as they emerged from the cauldron of war and from the wreck of letters and science, they were nevertheless bound to attack, if civil societies worthy of the name were to be constructed. How slow in gestation is the mother of truth we may see by comparing the schoolmen of the second medieval period with those of the first; in the enlargement of their view, the better furniture of their minds, and the deeper meaning of their distinctions: and when we compare with these later schoolmen the naturalists of the seventeenth century, we find not new acquirements only but also a new direction of the pursuit of truth.

It seems hardly comprehensible that great and stable societies have been built up on transcendental schemes of thought, upon conceptions poised as it were in the air. Without a system of morals no civil society could exist; yet if mankind must have waited for civil polity until some such system were built up from below, of scientifically tested materials, social constructions would have been virtually impossible. In morals, as in the arts, the art precedes the science; the intuitions of genius imagine social schemes of provisional validity, and new and lofty standards of fitness. But a social fabric thus born of a vision can bear no rough handling; and even the solid builders who would make a more permanent foundation upon positive conceptions, while seeking more or less deliberately to underpin the fabric, may, and often do, shake it to ruin.

Hence in all guardians of morals the dread of meddling with the reigning vision of truth; hence its sanctity, that no man shall try the stuff of which it is made. And the dangers of heresies from within are more fearful than those of alien attacks; social cohesion, the end of it all, is thereby more exposed to disintegration. Yet nevertheless, as the generations of men change, and as knowledge increases, men see from new points of view; and thus while for some the reigning vision retains its apparent solidity, for others its rays are broken or dissolved. Even John Henry Newman was compelled to teach the relativity of truth, and that a doctrine of development must be accepted. For every provisional synthesis then the time must come when the apparition of truth can no longer command united allegiance, and criterions begin to encroach upon sanctions. Broader and more stable foundations have, it is true, been rising almost insensibly, yet it may be long ere the superstructure rise into the heavenly light; in the lower work many will see no beauty and no hope, others will see safety in its enlargement and solidity. By these indeed the visions of the imagination are apt to be forgotten, or in the pressure of intellectual verification even despised; the mean level of conception may not indeed be lower, it may haply be higher, yet the highest, wherein truth may be revealed by illumination, is not divined in its full force, abundance and life. Great seers are wont to leave to others to find out, or even to care, what bottom they stood upon; yet only through transitory periods of a humbler duty than theirs can the bases be laid and enlarged for times of richer fruition. One of the profoundest of modern sayings was that of Freeman – that the end of modern material progress is to bring large societies up to the level of small ones.

This is the day of a great celebration; that on this anniversary I am worthy to take a place in the succession of your Orators is more than I dare to believe, that you have deemed me worthy is my encouragement. In private duty also I am bound to honour one of the greatest of the sons of the University of Cambridge, and the greatest member of the ancient and honourable house of Gonville and Caius College.

In some respects I am ill equipped for my office; of the history of the practice of Medicine from the time of Galen to the time of Harvey I am almost ignorant, I fear wilfully ignorant. Well indeed may we turn our eyes away from those centuries wherein one of the chief callings of man fell into unexampled and even odious degradation; yet I trust that in me this ignorance and this aversion may be compensated by some familiarity with the history of thought in the Middle Ages, a familiarity acquired during thirty-six years of abiding interest, and occasional study.

The discovery of the circulation of the blood by William Harvey is commonly regarded among scientific discoveries as pre-eminent if not unique. I can quote but two opinions on this matter, both taken beyond our own land. In France, Dr Daremberg exclaims “Voici Harvey! Comme au jour de la création le chaos se débrouille, la lumière se sépare des ténèbres!” In Germany, Dr Baas says that Harvey stands alone in respect of the world of life; that his discovery of the inner working of the microcosm takes a place equal to, if not indeed higher than, those of Copernicus, Kepler and Newton in respect of the macrocosm. It will be my endeavour to show that these judgments are historically justifiable.

To put the discovery of the systemic circulation of the blood in its true light, we must have some notion of the history of philosophy, science and medicine. Medicine, and herein it is in contrast with Theology and Law, had its sources almost wholly in the Greeks. Not only in the doctrine of the four elements of Empedocles, a doctrine which has survived almost to our own day², and in the physical theories of Heraclitus and Leucippus, did medicine, for good or ill, first find a scheme of thought, but in the schools of Hippocrates and of Alexandria it was based also, and far more soundly, upon natural history and anatomy. The noble figure of Galen, the first experimental physiologist and the last of the great Greek physicians, portrayed for us by Dr Payne in the Harveian Oration of 1896, stood eminent upon the brow of the abyss when, as if by some convulsion of nature, medicine was overwhelmed for fifteen centuries. To the philosophy of medicine, Galen had given more than enough; to its natural history he had contributed in the following of Hippocrates; to its discoveries he had given the greatest of all means of research, individual genius; to its methods he had given, but in vain, that indispensable method, practised first perhaps in history by Archimedes and the Alexandrians, of verification by experiment; a method, after Galen, virtually lost till the time of Gilbert, of Galileo and of Harvey.

In the growth of human societies small civilisations, however exquisite, have been sacrificed to the formation of vaster and vaster congregations of men; thus only, it would seem, is an equilibrium to be reached of sufficient stability for the highest ends of mankind. Greece, beautiful as was her bloom, penetrating as was her spirit, perhaps because of her very freedom of thought, never became a nation; her city states were too wilful to combine. The Macedonian power broadened the foundation of polity eastward and westward; and this work was carried as far perhaps as sword and fasces could carry it by the power of Rome. But even the Roman peace, bought as it was at the cost of learning and the arts, was but a mechanical peace; in the wilder, more turbulent and more heterogeneous peoples of the later Empire the bodies but not the wills of men were in subjugation. The great system of Roman Law, which Numa, the Moses of Rome, had invested with supernatural awe, had become but an external rule; even in Rome herself, poorer in people, poorer in commerce, poorer than ever in ideas, the sanction of patriotism was failing, and her citizens were held together for the most part by their baser and more dangerous passions³. For Eastern Europe the University of Constantinople established a compact and uniform system of thought, subtle prolix and acquisitive rather than original or profound; but in the West, under the Frank and later Northern devastations, the very traditions of learning and obedience were broken up; schools were closed, and even the art of writing was almost lost. Then it was that the cohesion and development of Western Europe were saved by a new and a wonderful thing. From the East, the home of religions, had spread, like an exhalation, Christianity, that religion which proves by its survival that it is the fittest sanction for the will of man. This religion, entering as a new spirit into the ancient fabric of Roman Empire, was to hold men’s service in heart and soul as well as in body; yet to this end no mere mystic or personal religion could suffice: clothing itself with the political and ritual pride and even with the mythology of the pagan Empire it inspired a new adoration; but it imposed also upon Europe a catholic and elaborated creed. To preserve the authority of the common faith not only must every knee be bowed, not only must every heart be touched, but to build and to repair its fabric every mind must also bring its service. How the scheme of the Faith was built up, how oriental ecstasy and hellenistic subtlety, possessing themselves of the machinery of Roman pomp, were wrought to this end, we may briefly consider.

As, politically, under Diocletian and Constantine the ancient world gave place to the new, so in the third century philosophy was born again in neo-platonism⁴, the offspring of the coition of East and West in Alexandria, where all religions and all philosophies met together. The world and the flesh were crucified that by the spirit, man might enter into God⁵. Pure in its ethical mood, neo-platonism, says Harnack, led surely to intellectual bankruptcy; the irruption of the barbarians was not altogether the cause of the eclipse of natural knowledge: to transcendental intuition the wisdom of the world had become foolishness. Yet even then, as again and again, came the genius of Aristotle to save the human mind. The death of Hypatia was the death of the School of Alexandria, but in Athens neo-platonism survived and grew. Proclus, ascetic as he was, was versed also in Aristotle; and he compelled the Eastern mysteries into categories: so that on the closure of the School of Athens by Justinian (a. d. 529) a formal philosophy was bequeathed to the Faith; the first scholastic period was fashioned, and the objects and methods of enquiry were determined for thirty generations. From Aristotle Europe adopted logic first, and then metaphysics, yet both in method and in purpose Origen and Augustine were platonists; rationalised dogma lived upon dialectic, and conflicted with mysticism; but logic, dogma and mysticism alike disdained experience.

Thus, no mere external sanction, stood the Faith; threefold: from the past it brought its pompous ritual, it appealed by its subtle dogmatic scheme to the intellects, and by its devotion to the hearts of men. Through the mirage of it, when its substance had waned, Copernicus, Galileo, and Harvey had to steer by the compass of the experimental method. This was their chief adversity, and of other adversities I have to speak.

The visitor to the Dominican Church of St Catherine at Pisa will see on its walls St Thomas of Aquino with the Holy Scriptures in his hand; prostrate beneath him is Averroes with his Great Commentary, but beside him Plato bearing the Timæus. It was the fortune of the Faith that, of all the treatises of Plato, the Timæus, the most fantastic and the least scientific, should have been set apart to instruct the medieval world; that the cosmical scheme of the Timæus, apparelled in the Latin of Chalcidius, – for there were then no Greek texts in the libraries of the West, – should for some 500 years have occupied that theoretical activity which Aristotle regarded as the highest good of man⁶. Again, those works of. Aristotle which might have made for natural knowledge fell out of men’s hands⁷, while in them, as Abélard tells us of himself, lay the Categories, the Interpretation, and the Introduction of Porphyry to the Categories, all in the Latin of Boetius⁸; treatises which made for peripatetic nominalism, but whereby men were versed rather in logic and rhetoric than in natural science. Thus Plato’s chimera of the human microcosm, a reflection of his theory of the macrocosm, stood beside the Faith as the second great adversary of physiology.

The influence of authority, by which Europe was to be welded together, governed all human ideas. As in theology was the authority of the Faith, so in the science and medicine of the first period of the Middle Ages was that of the neo-platonic doctrines, and, in the second period, of the Arabian versions of Galen and of Aristotle; furthermore in this rigid discipline metallic doctrine almost necessarily overbore life and freedom. It is not easy for us to realise a time when intellectual progress – which involves the successive abandonment of provisional syntheses – was unconceived; when truths were regarded as stationary; when reasons were not tested but counted and balanced; when even the later Averroists found final answers either in Aristotle or in Galen⁹. Thus in the irony of things it came to pass that Harvey was withstood by the dogma of Galen who, in his own day, had passionately appealed from dogma to nature.

Porphyry of Tyre, who lived in the 3rd century, may be called the founder of both Arabian and Christian scholastics. He was an Alexandrian, but of peripatetic rather than platonic opinions. In the Isagoge, or Introduction to the Categories, already mentioned as translated by Boetius about 500 a. d., he set forth plainly a problem which during the Middle Ages rent Western Europe asunder; a problem which, says John of Salisbury¹⁰, engaged more of the time and passions of men than for the house of Cæsar to conquer and govern the world; one indeed which even in our day and country is not wholly resolved.

The controversy lay between the Realists¹¹ and the Nominalists; and the issues of it, in the eleventh century, – at which time the “Dark Ages” passed into the earlier of the two periods of the Middle Ages, – were formulated on the realist side by William of Champeaux, while the Breton Rousselin, or Roscellinus, had the perilous honour of defining them on behalf of the nominalists¹². To see the depth of the difference we must step back a little, to a time when metaphysics and psychology were not distinguished from other spheres of science¹³, and all research had for its object the nature of being. Plato himself held ideas not as mere abstractions but in some degree as creative powers; and we shall see how potent this function became in the thought of the Middle Ages when, in the ardour of research into the nature of being, the modes of individuating principles were distinguished or contrasted with an ingenuity incomprehensible to Plato or Aristotle, or at any rate undesired by these greater thinkers. Aristotle avoided the question whether form or matter individuate; he held that there is no form and no matter extrinsic to the individual. But by the medieval realist every particular, every thing, was regarded as after some fashion the product of universal matter and individual form. Now “form” might be regarded, and severally was regarded, as a shaping, determinative force or principle, pattern type or mould, having real existence apart from stuff, or, on the other hand, as an abstract principle or pattern having no existence but as a conception of the mind of the observer. The realists roundly asserted that form is as actual as matter, and that things arise by their participation – without whiteness no white thing, without humanity no man; and not individuals only: for the realist, out-platonising Plato, genera and species also had their forms, either pre-existent (“universalia ante rem”), or continuously evolved in the several acts of creation (“universalia in re”). Indeed for the extreme realist every “predicamental modality” was “aliquid ens separatum”; for instance, the soul, the active intellect, the passive intellect, and so on: conversely, by fusing idea with will, for other philosophers realism would get pushed back into efficient reason or divine will, and almost vanish¹⁴. By this latter route the Sorbonne, originally opposed to the Thomists, became nominalist after all; as did those once pious realists the Augustinians and Cistercians. Setting aside then the extreme nominalists, who would have dissolved thought by declaring all creatures to be so individual as to be incomparable, – “pulverising existence into detached particulars,” as some one has put it – and that names of kinds are mere nouns, or indeed mere air (“flatus vocis”), the prevalent nominalists were content to deny to ideas, forms, principles, or abstractions any other existence than as functions of the human mind – as subjective conceptions. For Ockham, says Hauréau, an idea was but a modality of the thinking subject. Abstractions then for these thinkers were but mental machinery for analysis of the concrete. Aristotle was as obscure and inconsistent in his language herein, and often elsewhere, as he was profound and scrupulous; but when his works came to be studied as a whole, and in the original tongue, the influence of his method, rather than the close consistency of his language, told against realism: virtually he was a conceptualist, and he found reality, where Plato denied it, in the particular object of sense¹⁵.